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42 Cards in this Set

  • Front
  • Back
Striatum
- Caudate nucleus
- Putamen
Corpus striatum
- Caudate nucleus
- Putamen
- Globus pallidus
Lenticular nucleus
- Putamen
- Globus pallidus
Basal ganglia
- caudate nucleus
- putamen
- globus pallidus
- amygdala
- subthalamic nucleus
- substantia nigra
Inputs to putamen
motor and somatosensory cortex
Outputs of putamen
via globus pallidus:
1. primary motor cortex (M1)
2. premotor cortex
3. supplementary (M2)
Basal ganglia circuit
cerebral cortex->
basal ganglia->
thalamus->
cerebral cortex
pathways out of GPi:
1. from ventral GPi?
2. from dorsal GPi?
1. ansa lenticularis
2. lenticular fasciculus
The magnocellular portion of substantia nigra is the pars _______ .
compacta
The pars _______ of the substantia nigra consists of smaller cells and is considered part of the GPi.
reticulata
Inputs to the caudate and putamen are primarily from the (1)______ and the neurotransmitter is (2)______.
1. cerebral cortex
2. glutamate
Input nuclei of basal ganglia.
1. caudate nucleus*
2. putamen*
3. nucleus accumbens
(*caudate+putamen=striatum)
Processing nuclei of the basal ganglia
1. GPe
2. Subthalamic nucleus
3. ventral tegmental area
Output nuclei of the basal ganglia
1. GPi
2. Substantia nigra pars reticulata
3. ventral pallidum
Output neurotransmitter of basal ganglia
GABA
Two parts of the substantia nigra
1. pars compacta
2. pars reticulata
The magnocelluar portion of the substantia nigra is the pars _____.
compacta
The pars (1)_____ of the substantia nigra is composed of smaller cells and is considered to be part of the (2)____, the major output nucleus of the basal ganglia.
1. reticulata
2. GPi
What are the two pathways out of the GPi:
1. from ventral GPi
2. from dorsal GPi
1. ansa lenticularis
2. lenticular fasciculus
Match the following (re: basal ganglia):
- direct pathway, indirect pathway
- movement suppression, movement initiation
- direct pathway: movement initiation
- indirect pathway: movement suppression
GPi projects to which thalamic nuclei?
ventral anterior (VA) & ventrolateral (VL)
Basal ganglia basic circuit
cerebral cortex->
basal ganglia (striatum)->
thalamus (VA & VL)->
cerebral cortex
Basal ganglia DIRECT pathway
1. diagram it
2. neurotransmitters at each step
cerebral cortex-(glutamate)->
striatum-(GABA)->
GPi-(GABA)->
thalamic VA/VL-(glutamate)->
cerebral cortex
Basal ganglia INDIRECT pathway
1. diagram it
2. neurotransmitters at each step
cerebral cortex-(glutamate)->
striatum-(GABA)->
GPe-(GABA)->
STN-(glutamate)->
GPi-(GABA)->
thalamic VA/VL-(glutamate)->
cerebral cortex
To what part of the basal ganglia do substantia nigra inputs project?
Striatum (caudate+putamen)
What subtypes of dopamine receptors are associated with the indirect and direct pathways in the basal ganglia?
Are these receptors inhibitory or excitatory?
- indirect: D2, inhibitory
- direct: D1, excitatory
How do D1 and D2 receptors exert their effects?
D1 (excitatory) increases cAMP. D2 (inhibitory) decreases cAMP.
What type of cell receives DA inputs in the basal ganglia direct pathway? Effect?
- GABAergic medium spiny neurons (projection neurons)
- Excites them (D1 receptors), so they release GABA onto GPi/SNr.
- GPi/SNr then releases LESS GABA onto thalamic VA/VL.
- VA/VL then releases MORE glutamate onto motor cortex.
- MORE MOVEMENT.
What type of cell receives DA inputs in the basal ganglia indirect pathway? Effect?
- GABAergic medium spiny neurons (projection neurons)
- Inhibits them (D2 receptors), so they release less GABA at the GPe.
- Disinhibits GPe.
- GPe releases more GABA at STN.
- STN releases less glutamate at GPi/SNr
- GPi/SNr releases less GABA onto VA/VL
- Disinhibits VA/VL
- VA/VL releases more glutamate onto motor cortex
- MORE MOVEMENT
What effects do dopamine have on the direct/indirect pathways (activate or inhibit)? On movement?
DA activates the direct pathway (D1) and inhibits the indirect pathway (D2), both of which leads to increased movement.
What type of cell receives dopamine inputs in the striatum? How are they different in the direct vs. indirect pathways?
GABAergic medium spiny neurons, the projection neurons of the striatum. Direct have D1 receptors (excitatory). Indirect have D2 receptors (inhibitory).
Chorea is typically caused by a lesion of the ____ of the basal ganglia.
Caudate nucleus
Athetosis is typically caused by a lesion of the ____ of the basal ganglia.
Globus pallidus (or its projections)
What's a key difference between Huntington's disease and levodopa induced dyskinesia of Parkinson's disease? (Hint: associated S/S)
Levodopa induced dyskinesia is not associated with cognitive or behavioral sequelae.
Hemiballismus is generally caused by a (1)[contralateral or unilateral?] lesion of the (2)____ or its projections.
1. contralateral
2. subthalamic nucleus
At the molecular level, Huntington's disease is associated with expansion of (1)____. This phenomenon is referred to as genetic (2)____.
1. CAG (a trinucleotide repeat)
2. anticipation
Match these disorders...
- Parkinson's, Huntington's, hemiballismus

with these anatomical structures:
- subthalamic nucleus, striatum, substantia nigra pars compacta
Parkinson's: SNc
Huntington's: striatum
Hemiballismus: STN
Describe the pathophysiology of hemiballism in terms of the circuit involved.
- Lose STN glutamatergic input to the GPi
- Less GABA from GPi to VA/VL
- Disinhibits VA/VL
- VA/VL releases more glutamate at motor cortex
- Hyperkinetic movement disorder
Hemiballism involves damage to the [direct or indirect?] pathway.
indirect
Parkinson's disease involves loss of dopaminergic neurons in the substantia nigra pars compacta. This affects the [direct/indirect?] pathway.
BOTH direct and indirect
True or false?

Parkinson's disease leads to degeneration of substantia nigra only, sparing other monoaminergic nuclei such as the locus ceruleus.
FALSE. Locus ceruleus degenerates as well. PD pts. also have decreased levels of 5HT, another monoamine.
Relation between the locus ceruleus and the substantia nigra
- Locus ceruleus projects to the substantia nigra.
- Both are monoaminergic.
- Locus ceruleus: NE
- Substantia nigra: DA